1. Field of the Invention
The invention relates to external storage devices with a thin thickness type that are releasably or exchangeably used for storage equipment and devices as an external storage medium.
2. Description of the Related Art
Two types of storage devices (memory elements), which are capable of recording and saving various data, have been utilized, namely, one is incorporated and fixed within storage equipment or devices, and the other is releasably or exchangeably incorporated in the storage equipment or devices. For the latter type, the external storage device, for example, floppy disks can freely be attached or detached by one touch operation. The floppy disks"" being the storage mediums can separately be used depending on purpose and object. This therefore produces easier data reduction with optional classification, recording, and saving. However, a problem arises in the floppy disks described, where first, the data are occasionally disappeared on recording or saving the data to produce disadvantage in less reliability together with its slower access time. Next, when employing the smaller sized floppy disks in response to a miniaturization policy, a storing area of the storage medium is correspondingly smaller to reduce storage capacity, this thus gives an adverse effect in realizing the compact size and high capacity therefor. On the other hand, in semiconductor memory devices used as an external storage device such as IC memory cards there can largely solve the problems in the floppy disks such as less reliability on recording and saving the data and the slower access time. In general, the IC memory cards comprise, a functional circuit in which circuit components containing the semiconductor memory devices or elements are mounted on substrates, a resin case incorporating therein with the functional circuit as an inside attachment, a cover for covering and sealing an opening surface of the resin case, and external connection terminals such as two piece connectors which are attached on one edge of the resin case and electrically connect the functional circuit and the storage equipment/device.
However, the IC memory cards are assembled with a large amount of components and parts, where a relatively complicated structure is required with limitation to a thickness of the IC memory card, resulting in difficulty to realize compact size. Further, disadvantages arise in practical use because of lower cost performance or production yields on mass producing in addition to the less releasability or fluctuated releasability to the storage equipment and device.
An object of the invention is to provide an external storage device having a simplified structure with satisfactory production yields.
Another object of the invention is to provide an external storage device with a high reliability in view point of recording and saving the data.
Further another object of the invention is to provide an external storage device with a rapid access time.
Still another object of the invention is to provide an external storage device with high releasability for the storage equipment and device.
An external storage device according to the invention is comprised of an external storage device main and an external storage device unit, detail of which is as follows. An external storage device main includes, a thin type external storage device module formed into a one-sided sealed package from a storage medium series element containing at least one non-volatile semiconductor memory device, and a flat type external connection terminal connected to an input/output terminal of the storage medium series element and led and exposed to a backside of the external storage device module. An external storage device unit includes, a mechanism for engaging, insertedly attaching and detaching the external storage device main, an resilient contact electrically connecting to the flat type external connection terminal of the external storage device main.
In the external storage device according to the present invention, the external storage device main may preferably be formed into a one-sided sealed package structure. However for easier handling, the external storage device main may preferably be used in the form of a card type structure attached on the supporting plate. The external storage device unit may preferably be assembled and incorporated with a part or entire of the control circuit components or parts such as semiconductor elements constituting the control function.
The external storage device has a higher integration with a memory capacity to an extent of 16 M-bits per chip, in addition, is provided as a main memory with a non-volatile semiconductor memory device which does not require a power supply for maintaining storage. The main memory is formed into the one-sided sealed package to produce a thin type external storage device module or external storage device main. Thus, the external storage device module is easily achieved in a thin structure and at a lower cost by such as a transfer mold system. A mount of the external storage device main to the external storage device unit is performed by an insertion system at the side surface of the external storage device unit in the card type. The external connection terminal is led and placed in a manner of plane to the rear-side of the external storage device main, hence, a high reliable electrical connection can easily be performed even when attaching and detaching by a one touch system for the external storage device unit. In the card type, the external storage device itself maintains and exhibits satisfactory releasability for the storage equipment and devices. The card type external storage device main can readily be attached and detached for the external storage device unit, and realizes a function of the floppy disk device as it is, and simultaneously a reliability of electrical connecting and disconnecting due to the attaching and detaching can be improved.